3DViewnix - Demo of a commercial package.
FP Image - View/Process Floating Point and integer images in Windows 95/98/NT. Formats include DICOM and user defined formats. Includes a image processing scripting language.
FP Image for Windows - Scientific/Medical imaging software. Formats include floating point, integer and DICOM. Built-in image processing scripting language, batch processing, 3D solid modeling. ( FP Image)
FreeImage - FreeImage is an Open Source project for developers who would like to support popular graphics image formats like BMP, JPEG, TIFF, PNG, RAS, PNM, PCX, TGA in their C++ applications for Windows. (by Floris van den Berg, Hervé Drolon)
GD - a graphics library for GIF creation - provides GIF read/write code in a C library. It also provides minimal image manipulation functions (lines, arcs, text, colors). Includes versions for Unix and Windows systems. (by Thomas Boutell / Boutell.Com)
GNU Image Manipulation Program (GIMP) - Photoshop-style image editor.
ImageMagick - Load, display, process, save, and convert images in many formats. Works on Unix, Linux, Windows, and Mac. Includes a display program, a converter, screen capture, animator, and more.
JPEG - Library source code and simple display tools.
Jpeg/Dicom library - MFC source code for jpeg/dicom/twain (commercial, but limited free version available)
C++ MFC source code for Dicom, Jpeg, Dib codecs plus TWAIN manager. Up to 32 bits per channel (=96 bpp in RGB mode), 12-16 bits per channel jpeg codec. (by Paolo Brandoli)
Mesa - Mesa is a 3-D graphics library with an API which is very similar to that of OpenGL.
MPEG-1 player and encoder
Also: FAQ and fancy VCR-like interface using Motif.
NIH Image - for Macintosh
TIFF - Library source code and tools
VisGenie: a Generic Video Information Visualization System - VisGenie is a Generic Video Information Visualization System
VisGenie is a generic video based information visualization system on computers running Microsoft Windows operating systems, capable of rendering video data in a manner suitable for the research / development purpose instead of entertainment, and visualizing the associated metadata streams. (by Yong Wang, Lexing Xie, and Shih-Fu Chang / Digital Video | Multimedia (DVMM) / Columbia University)
Volumetric Image Display and Analysis (VIDA) - Demo of a commercial package.
XAnim - X11 display tool.
Supports many animation and image formats ("everything" except mpeg). Notes on integrating xanim with Web clients/MIME are also available.
XLI - X11 display tool.
Not as featureful as xv but it understands nearly all the same formats and displays images much more quickly. Source archive is available.
XV - X11 Image Display tool.
Provides an amazing assortment of image operators, reads and writes images in many different formats.
Ygl - Emulation of SGI GL library for X11.